10 votes
Accepted

How to calculate Special Quasirandom Structure with local ordering?

Often we are hung up on the idea of making sure we generate an SQS of a size (i.e. # of atoms) that matches the composition of our system. For instance, in the case of $A_3B$ we would generally take ...
Hitanshu Sachania's user avatar
10 votes

Generating special quasirandom structures (SQS) for surface calculations?

First of all, it's better to define the terms here because probably not all the people here are familiar with SQS right away. SQS is an abbreviation for special quasirandom structures. The ...
Mithridates the Great's user avatar
9 votes

k-points convergence for special quasirandom structures (SQS) of the same material containing different # of atoms

Very good question. I think that when you select one of the many different disordered structures as been a representative one, that structure is not disordered anymore, it is an structure as any ...
Camps's user avatar
  • 23.3k
6 votes
Accepted

Lattice representation: change of unit cell

I will start by re-stating your question to make sure I understand what you mean. You have a cell with lattice vectors written in Cartesian coordinates as follows: $$ \begin{pmatrix} \mathbf{a}=\hat{\...
ProfM's user avatar
  • 11k
6 votes

Lattice representation: change of unit cell

I used the structure manipulation scripts provided by AIRSS to generate the conventional cell associated with your primitive cell. I think AIRSS uses Spglib under the hood for this task, so you could ...
wcw's user avatar
  • 1,893
5 votes

Supercell model for a disordered system in phonon calculations using the harmonic approximation

If you have a system without periodicity like your disordered solid solution, then you should use a $1\times1\times1$ $\mathbf{q}$-point grid for a phonon calculation (equivalent to a $1\times1\times1$...
ProfM's user avatar
  • 11k
4 votes
Accepted

Why does mcsqs change the space group of generated SQS?

These are some general comments about modelling disorder which I think address your question, but note I cannot provide specifics about the codes you are using. Imagine a simple configuration with ...
ProfM's user avatar
  • 11k
4 votes

Special quasirandom structures vs virtual crystal approach

For special quasirandom structures, the main advantage is that treating the atoms explictly allows the cell shape and ionic positions to be relaxed, capturing local atomic distortions which play a ...
Brandon Bocklund's user avatar
4 votes
Accepted

How to accelerate mcsqs to get quasi-random structure?

mcsqs is not supported by mpi. Each process of mcsqs can be run on only one core. However, as a Monte Carlo method, you can still parallelize. You can concurrently run multiple processes on different ...
Akram Hafez's user avatar
3 votes

Generating special quasirandom structures (SQS) for surface calculations?

There are two different perspectives here. The first one is the creation of the SQS structure itself accomplished through the ATAT package, for example. The second one is the calculation of the slab ...
Anibal Bezerra's user avatar
3 votes

Changing orientation of SQS structure generated from ATAT

In general ,SQS changes shape of cell to find best quasi random structure, here you are trying for an orthogonal cell, but as output you are getting non-orthogonal ...
Pranav kumar's user avatar
  • 4,083
3 votes

Cluster correlations for a perfectly random state in the Alloy Theoretic Automated Toolkit

Caution: Self answer ahead! Let's understand it with an example of a binary $AB$ compound. A correlation function for a particular type of cluster (pair, triangle, tetrahedron, etc.), $\rho$, is ...
Hitanshu Sachania's user avatar
1 vote

Generating special quasirandom structures (SQS) for surface calculations?

As Anibal points in his answer, generating the SQS and using it for a surface calculation are two separate things, and shouldn't affect each other. You would still take all precautions as usual while ...
Hitanshu Sachania's user avatar

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